The present invention relates to stuffing box sealing arrangements in general, and more particularly to a stuffing box sealing arrangement for a rotary shaft extending into a pressure space.
There are already known various constructions of stuffing box sealing arrangements, among them such which include two sealing chambers in which there are accommodated respective stuffing sealing rings which may have different properties. A distribution chamber for lubrication is arranged between these two sealing chambers, this distribution chamber being mounted on the shaft for relative axial displacement. In this construction, the lubrication water penetrates from the distribution chamber into the two adjacently situated sealing chambers where it comes into contact with and lubricates and cools the region of contact of the outer circumferential surface of the shaft with the respective stuffing sealing rings, as a result of which the stuffing sealing rings are prevented from becoming excessively hot. Only a single stuffing box gland is being used in this known stuffing box sealing arrangement for the pressing of the stuffing sealing rings in both of the sealing chambers, this gland acting directly on the stuffing sealing rings of the adjacent, that is, of the outer, sealing chamber and indirectly via the distribution chamber on the stuffing sealing rings of the inner sealing chamber, that is, of the sealing chamber that is situated closer to the pressure space. It will be easily appreciated that a purposeful application of different forces to the stuffing sealing rings accommodated in each of the two sealing chambers correspondingly to the requirements for the two sealing chambers is not possible in this arrangement. Rather, there exists the danger that, when an insufficient sealing effect is encountered at the stuffing sealing rings accommodated in one of the sealing chambers and the stuffing box gland is tightened to overcome such diminished sealing action, the stuffing sealing rings received in the other sealing chamber are compressed excessively and, in this manner, supply of lubrication water to such excessively pressed stuffing sealing rings is prevented or significantly curtailed. This, in turn, results in excessive heating and possible eventual destruction of such stuffing sealing rings.